Rollback SHELL UID check for CarrierConfigLoader

When a test calls adoptShellPermissionIdentity before
calling a command, it doesn't adopt the shell UID, only
the permissions. So, we can not use
Binder#getCallingIdentity to determine it the API is
being called as part of a test. For now, we must only
use MODIFY_PHONE_STATE until a better pattern is
established.

Test: Manual
Bug: 131185660
Change-Id: I59d32a2e36950b2485e1a46a25e3724928676219

telephony/java/android/telephony/CarrierConfigManager.java

@@ -3371,8 +3371,7 @@ public class CarrierConfigManager {
      * May throw an {@link IllegalArgumentException} if {@code overrideValues} contains invalid
      * values for the specified config keys.
      *
-     * NOTE: This API is meant for testing purposes only and may only be accessed from the shell UID
-     * during instrumentation testing.
+     * NOTE: This API is meant for testing purposes only.
      *
      * @param subscriptionId The subscription ID for which the override should be done.
      * @param overrideValues Key-value pairs of the values that are to be overridden. If set to